Apple has released its most expensive iPhone yet - a smartphone that will cost an eye-watering $999.

Company boss Tim Cook called the new iPhone X the "future of the iPhone", and announced it will feature new facial recognition technology called Face ID.

It goes on sale on November 3.

The software uses infrared sensors among others to build a dot pattern and recognise a user's face through machine learning techniques - even in the dark.

As well as being used to unlock the device, Face ID technology can also be used to create Animoji - animated emoji controlled by the user's face. The larger screen, which fills the front of the device, also uses OLED screen technology for the first time.